1. Field of the Invention
This invention concerns a device to load reinforcement rods. To be more exact, the invention concerns a device suitable to cooperate with an excavation equipment in moving the drilling shaft before and after the drilling of a hole and in feeding on the excavation equipment the non-recoverable reinforcement rods employed in lengthwise reinforcements in tunnels.
2. Discussion of Prior Art
The device of the invention and the excavation equipment are normally carried on an excavation machine operating at the working face.
The state of the art includes various methods and devices employed in the reinforcement of tunnels.
One of the systems most often used consists in carrying out a series of lengthwise drillings about the vault of the tunnel.
At the end of each drilling step, which is carried out by means of suitable tools on a shaft, the shaft is withdrawn from the hole made in the tunnel wall and a cement agglomerate is injected into the hole.
Thereafter, a non-recoverable reinforcement rod, having a length substantially the same as that of the hole thus made, is inserted into the cement agglomerate so as to complete the reinforcement.
The cycle is repeated to make each hole, and therefore there is a continuous handling of the drilling shaft alternated from time to time with the feeding of new reinforcement rods for insertion into the holes made in the wall.
The action of drilling and inserting the rods is normally carried out by means of one and the same excavation equipment borne on an operating machine.
The operating machine brings the excavation equipment with the drilling shaft from time to time to the hole to be made. As each hole is made, the excavation equipment is normally withdrawn to one of its two lower positions at the sides of the machine, where the drilling shaft is removed by hand and the reinforcement rod to be inserted is fitted.
The excavation equipment is then brought back again to the hole made beforehand and filled in the meantime with the cement agglomerate.
When the reinforcement rod has been inserted, the excavation equipment is withdrawn once more to its position for the drilling shaft to be fitted, and the cycle is repeated in the same way for each hole to be made.
The operating steps described above entail a considerable use of manpower and very long times for execution.
Moreover, after the drilling, the excavation equipment is displaced for the reinforcement rod to be loaded and the subsequent positioning of the reinforcement rod on the drilling axis with the required accuracy becomes a problem.
The problems are worsened when it is realized that the drilling shafts and reinforcement rods may have a length of twenty metres or more.